System and method for manufacturing crowns for teeth

ABSTRACT

A system and method for fabricating dental crowns and bridgework includes the steps of: selecting one or more model teeth; forming a mold around the model tooth using a soft flexible material; removing the model tooth from the mold; adding wet dental restoration material to the mold and vibrating the mold; pressing framework into the wet restoration material; vibrating the mold and removing moisture; allowing the restoration material to dry and removing the molded crown or bridgework from the mold; trimming off excess restoration material and adding restoration material to the margin area as needed; baking the crown or bridgework in an oven without the mold and removing the crown or bridgework from the oven when the restoration material is at least partially cured.

This patent application is a Continuation-In-Part (CIP) patentapplication based on non-provisional patent application Ser. No.15/902,719 filed Feb. 22, 2018, which is based on provisional patentapplication Ser. No. 62/477,214 filed Mar. 27, 2017 and provisionalpatent application Ser. No. 62/462,668 filed Feb. 23, 2017.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention is directed to a system and method for fabricatingdental crowns and bridgework, and more particularly to a system andmethod that greatly reduces the time and simplifies the task offabricating highly aesthetic dental crowns and bridgework that haveexcellent shape and anatomy and vital florescence.

Discussion of the Related Art

The fabrication of crowns and bridges has always been a time consumingand expensive process, requiring a considerable amount of skilled(artisan) labor to custom fit crowns and bridges for each case.Traditionally, a technician is required to prepare a pasty mixture of aceramic powder and a liquid which gradually dries into a packed powder.While it is drying, the technician must mold and carve the pasty mixtureinto a shape resembling the natural tooth it is replacing, or in thecase of an all ceramic crown, the technician must also match thecontours of the tooth stump to which it is to be affixed. Not only isthe shaping operation time consuming and difficult, but there is alsothe problem of the proper blending of colors in order to match the colorof the teeth to each other or to those natural teeth adjacent to the onebring fabricated. In many instances, the resultant fabricated crown orbridge does not have a vital appearance and is easily discernible fromthe remaining teeth.

SUMMARY OF THE INVENTION

A system for fabricating dental crowns and bridgework uses a siliconcomposition or like soft and pliable material that is easily formed inless than ten minutes. The soft material is molded over real teeth orartificial teeth (either being referred to hereinafter as “model teeth”or “model tooth”) to create a crown mold and a bite mold. This providesthe desired perfect anatomical shape. The soft mold is then placedwithin a prefabricated model of the patients teeth. Next, the upper andlower teeth of the model are pressed together so that the soft moldengages the opposing teeth of the model. This establishes the bite ofthe opposing teeth and perfect shape crown or bridgework. The prototypetooth (for a crown) or prototype teeth (for a bridge) is then removedfrom the soft mold and wet dental restoration material is placed in themold. Next, the mold is vibrated to create the incisal in a thin layerto include the occlusal, buccal, lingual, and facial walls. At thisstage, the molded incisal or shell can be removed from the mold forsubsequent use. Alternatively, the incisal can remain in the soft moldand the body (i.e., more wet restoration material) is then added to themold and vibrated using a variable speed vibration machine. Next,framework is pressed into the wet restoration material or other materialforming the body until it reaches the established point or margin area.The mold is vibrated and moisture is removed from the wet restorationmaterial. This can be done using a tissue. Once the restoration materialis dry, the molded crown or bridgework is removed by opening theflexible mold and pushing the new teeth (i.e., crown or bridgework) outof the soft mold. Excess material is cut away along the lower marginarea and restoration material can be added to the margin area as needed.The molded crown or bridgework is then baked in an oven for between 40percent to 70 percent of the cure time. The crown/bridgework is thenremoved when partially cured so that the restoration material is stillsoft and easy to shape and carve to adjust the bite if needed forcompletion. In another embodiment of the invention, a block formation oroverbuilt (exaggerated build-up) crown or bridgework (i.e., single unitor multiple unit) is molded using the soft mold, and is removed from theoven at 50%-80% of the cure time. Next, a CAD CAM system is used toallow precision cutting and formation by a milling machine so that nohand work is needed. In either embodiment, the crown/bridgework can beglazed back into the oven for completion.

OBJECTS AND ADVANTAGES OF THE INVENTION

Considering the forgoing, it is a primary object of the presentinvention to provide a system for producing dental crowns and bridgesthat eliminates between fifty percent and eighty percent of the labornormally involved in the currently used processes of producing dentalcrowns and bridges.

It is a further object of the present invention to provide a system forproducing dental crowns and bridges that produces perfectly shaped andanatomically correct crowns and bridges to provide an extremely naturalappearance.

It is a further object of the present invention to provide a system forproducing dental crowns and bridges of the desired aesthetically vitalcolor that match the shade guide.

It is a further object of the present invention to provide a system forproducing dental crowns and bridges with high quality control.

It is a further object of the present invention to provide a system forproducing dental crowns and bridges that are vital fluorescent.

It is a further object of the present invention to provide a system forproducing dental crowns and bridges having high end aesthetics.

It is a further object of the present invention to provide a system forproducing dental crowns and bridges that allows an average dentalceramist to create dental crowns and bridges that are on the level of ahighly skilled artisan in the field of dental prosthetics in less thanhalf the time normally required by a skilled artisan to create dentalcrowns and bridges using existing techniques, materials, machinery andsystems.

It is a further object of the present invention to provide a system forproducing dental crowns and bridges which eliminates the need forgrinding and buildup, as well as unnecessary waste of materials (e.g.,porcelain).

It is a further object of the present invention to provide a system forproducing dental crowns and bridges which eliminates the need formultiple bakes in a porcelain oven.

It is a further object of the present invention to provide a system forproducing dental crowns and bridges which eliminates the need to carvethe anatomy into the crown or bridgework with a high speed air turbineor brush.

It is a further object of the present invention to provide a system forproducing dental crowns and bridges which creates perfect anatomicallycorrect buccal, lingual and facial walls that are extremely vital andnatural in appearance.

It is a further object of the present invention to provide a system forproducing dental crowns and bridges that saves fifty percent to eightypercent of time compared to existing techniques and systems in therelated art.

It is a further object of the present invention to provide a system forproducing dental crowns and bridges which can be used to create a singleunit (i.e., crown for one tooth) or multiple units, as well as a fullmouth rehabilitation including upper and lower bridgework.

It is a further object of the present invention to provide a system forproducing dental crowns and bridges wherein the incisal can be pressedby the oven a first time and a body of the crown can be pressed during asecond time or process for individual blending of different incisals andcolors.

It is a further object of the present invention to provide a system forproducing dental crowns and bridges that can be used with any moldabledental restoration material.

It is a further object of the present invention to provide a system forproducing dental crowns and bridges that can be used with metal crownsand bridges or ceramic crowns and bridges.

It is a further object of the present invention to provide a system forproducing dental crowns and bridges that can be used on zirconia copingwhile being very vital and aesthetically pleasing.

It is a further object of the present invention to provide a system forproducing dental crowns and bridges wherein a block formation oroverbuilt (i.e., exaggerated size) tooth formation is molded in a softmold and then 60%-80% cured at which time the final crown or bridgeworkis cut by a milling machine with the use of a CAD CAM system.

It is a further object of the present invention to provide a system forproducing dental crowns and bridges that separates interproximal area onbridgework and rounds off teeth perfectly which saves a significantamount of bench time and eliminates the need for multiple bakes in anoven.

These and other objects and advantages of the present invention are morereadily apparent with reference to the following detailed description.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention is directed to a system and method for fabricatingdental crowns and bridgework using various dental restoration materialssuch as, but not limited to porcelain or zirconia. To begin, real teethor artificial teeth (i.e., “model teeth”) are selected for a particularpatient that will be fitted with the fabricated crown or bridgework. Themodel tooth or teeth are selected to match the anatomy of the patientand should be slightly larger to allow for shrinking of the dentalrestoration material during fabrication of the crown or bridgework.Next, a silicon composition or like soft and pliable material is moldedover the model teeth to establish a crown and bite mold that providesthe desired perfect anatomical shape. The soft mold is then placedwithin a prefabricated model of the patient's teeth that has upper andlower teeth replicating the patient's upper and lower teeth. Next, theupper and lower teeth of the model are pressed together to establish thebite of the opposing teeth and perfect shape crown or bridgework. Themodel tooth (or teeth) is then removed from the soft mold and a layer ofwet dental restoration material (e.g., porcelain or zirconia) is appliedto the inner walls of the mold where the prototype tooth was removed(i.e., the mold cavity). Next, the mold is vibrated to create theincisal in a thin layer to include the occlusal, buccal, lingual, andfacial walls. Next, more restoration material for the body is added tothe mold and vibrated using a variable speed vibration machine. Theframework is then pressed into the wet restoration material forming thebody until it reaches the established point or margin area. Theframework is prefabricated to be congruent with the shape of thepatient's tooth stump to which the crown or bridge is to be affixed. Themold is vibrated and moisture is removed from the wet restorationmaterial using a tissue or other method. Once the restoration materialis dry, the molded crown or bridgework is removed from the mold byopening the flexible mold and pushing the new teeth (i.e., crown orbridgework) out of the soft mold and into a tissue. Excess material iscut away along the lower margin area and restoration material can beadded to the margin area as needed. The molded crown is then baked in anoven for between forty percent and seventy percent of the cure time. Thecrown/bridgework is then removed when partially cured so that therestoration material is still soft and easy to shape and carve to adjustthe bite if needed for completion. In another embodiment of theinvention, a block formation or overbuilt (exaggerated build-up) crownor bridgework (i.e., single unit or multiple unit) is molded using thesoft mold, and is removed from the oven at 50%-80% of the cure time.Next, a CAD CAM system is used to allow precision cutting and formationby a milling machine so that no hand work is needed. In eitherembodiment, the crown/bridgework can be glazed back into the oven forcompletion.

While the present invention has been shown and described in accordancewith a preferred and practical embodiment, it is recognized thatdepartures from the instant disclosure are fully contemplated within thespirit and scope of the present invention which is not to be limited,except as defined in the following claims as interpreted under theDoctrine of Equivalents.

What is claimed is:
 1. A method for fabricating dental crowns comprisingthe steps of: selecting at least one model tooth; forming a flexiblemold around the selected model tooth using a soft, pliable and flexiblemolding material; removing the at least one model tooth from theflexible mold to provide a mold cavity for forming the dental crown;applying wet dental restoration material to at least partially fill themold cavity; pressing prefabricated framework into the wet dentalrestoration material; vibrating the flexible mold and removing moisturefrom the wet dental restoration material; removing the molded crown withthe prefabricated framework from the flexible mold prior to curing byopening the flexible mold and pushing the molded crown out of theflexible mold; placing the removed molded crown in an oven without theflexible mold and baking the molded crown to at least partially cure thedental restoration material; and removing the molded crown from theoven.
 2. The method as recited in claim 1 wherein the step of selectingat least one model tooth further comprises the steps of: placing one ormore model teeth in a prefabricated model of the patient's teeth in thelocation where the crown is to be fitted; comparing the one or moremodel teeth to adjacent and opposing teeth in the prefabricated model;and selecting the at least one model tooth that conforms with the size,shape and anatomy of the patient's adjacent and opposing teeth asreplicated on the prefabricated model.
 3. The method as recited in claim1 further comprising the step of: trimming off excess dental restorationmaterial along a lower margin area of the crown after the step ofremoving the molded crown from the mold.
 4. The method as recited inclaim 1 further comprising the step of: adding dental restorationmaterial along a lower margin area of the crown after the step ofremoving the molded crown from the mold.
 5. The method as recited inclaim 1 further comprising the steps of: carving and shaping the moldedcrown to final form after removing the molded crown from the oven; andplacing the molded crown in the oven for a second bake after the step ofcarving and shaping the molded crown.
 6. A method for fabricating dentalcrowns comprising the steps of: forming a flexible mold using a soft,pliable and flexible molding material to create an exaggerated size moldcavity; applying wet dental restoration material to the mold cavity forforming an exaggerated size molded crown; pressing prefabricatedframework into the wet dental restoration material; vibrating theflexible mold and removing moisture from the wet dental restorationmaterial; removing the exaggerated size molded crown with theprefabricated framework from the flexible mold prior to curing byopening the flexible mold and pushing the molded crown out of theflexible mold; placing the removed exaggerated size molded crown in anoven without the flexible mold and baking the molded crown until thedental restoration material is between 50% and 80% cured; removing theexaggerated size molded crown from the oven with the dental restorationmaterial partially cured; and using a CAD CAM system for precisioncutting and formation of the molded crown using a milling machine.
 7. Amethod for fabricating bridgework comprising the steps of: selecting atleast one model tooth; forming a flexible mold around the selected modeltooth using a soft, pliable and flexible molding material; removing theat least one model tooth from the flexible mold to provide a mold cavityfor forming the bridgework; applying wet dental restoration material toat least partially fill the mold cavity; pressing prefabricatedframework into the wet dental restoration material; vibrating theflexible mold and removing moisture from the wet dental restorationmaterial; removing the molded bridgework with the prefabricatedframework from the flexible mold prior to curing by opening the flexiblemold and pushing the molded bridgework out of the flexible mold; placingthe removed molded bridgework in an oven without the flexible mold andbaking the molded bridgework to at least partially cure the dentalrestoration material; and removing the molded bridgework from the oven.8. The method as recited in claim 7 wherein the step of selecting atleast one model tooth further comprises the steps of: placing one ormore model teeth in a prefabricated model of the patient's teeth in thelocation where the bridgework is to be fitted; comparing the one or moremodel teeth to adjacent and opposing teeth in the prefabricated model;and selecting the at least one model tooth that conforms with the size,shape and anatomy of the patient's adjacent and opposing teeth asreplicated on the prefabricated model.
 9. The method as recited in claim7 further comprising the step of: trimming off excess dental restorationmaterial along a lower margin area of the bridgework after the step ofremoving the molded bridgework from the mold.
 10. The method as recitedin claim 7 further comprising the step of: adding dental restorationmaterial along a lower margin area of the bridgework after the step ofremoving the molded bridgework from the mold.
 11. The method as recitedin claim 7 further comprising the steps of: carving and shaping themolded bridgework to final form after removing the molded bridgeworkfrom the oven; and placing the molded bridgework in the oven for asecond bake after the step of carving and shaping the molded bridgework.12. A method for fabricating bridgework comprising the steps of: forminga flexible mold using a soft, pliable and flexible molding material tocreate an exaggerated size mold cavity; applying wet dental restorationmaterial to the mold cavity for forming an exaggerated size moldedbridgework; pressing prefabricated framework into the wet dentalrestoration material; vibrating the flexible mold and removing moisturefrom the wet dental restoration material; removing the exaggerated sizemolded bridgework with the prefabricated framework from the flexiblemold prior to curing by opening the flexible mold and pushing the moldedbridgework out of the flexible mold; placing the removed exaggeratedsize molded bridgework in an oven without the flexible mold and bakingthe molded bridgework until the dental restoration material is between50% and 80% cured; removing the exaggerated size molded bridgework fromthe oven with the dental restoration material partially cured; and usinga CAD CAM system for precision cutting and formation of the moldedbridgework using a milling machine.